Question about Road Capacity

Lennoxschips

Hi, I post fairly regularily here and I was wondering if anybody could help me regarding road/motorway capacities. For my college project I have analysed traffic growth in the Rotterdam area between now and 2015, including the extra traffic that will be caused by the expansion of the port area. For each route I have predicted how many thousands of vehicles per day will use the road. I was wondering if anybody knew of any resources regarding road/motorway capacity, i.e. regarding what type of road is suited for X thousands of vehicles per day. The only thing that I know is that a dual carriageway has a capacity of roughly 50,000 vehicles a day.

I am analysing routes within a range of 27,000 and 160,000 vehicles per day.

Thanks for taking the time to read this, any help or links would be very much appreciated.

daymobrew

Contact the National Roads Authority (NRA). I know they monitor traffic flows and will know road capacities.

BTW, they also have multiple weather stations.

MrPudding

Contact the DTO as well. Apparently they use various medods to calculate road capacity.

MrP

Lennoxschips

I've contacted the NRA already but didn't think of the DTO. Will contact them too.

I'll let ye know the results.

If anyone has any direct links or knowledge please feel free to post it.

Thanks again.

Victor

Some one had an link recently about the numbers of vehicles different road types, I think they were advocating every new road be a dual carriageway.

Lennoxschips wrote:

I am analysing routes within a range of 27,000 and 160,000 vehicles per day.

Are you counting trucks the same as cars the same as bicycles?

Typically,

1 truck = 2 PCU
1 bus = 2 PCU
1 car = 1 PCU (passenger car unit)
1 bicycle / motorbike = 0.5 pcu

What is your peak -v- off-peak profile like? Daily capacity is less than 24 x hourly capacity.

Are you taking railfreight and barges (important on the Rhine system) into account?

http://www.bueker.net/trainspotting/maps_benelux.php

http://www.sporenplan.nl/html_nl/sporenplan/ns/ns_normaal/start.html (clickable links)

Hotblack Desiato

1 bicycle / motorbike = 0.5 pcu

That's probably reasonably accurate in flowing traffic, but doesn't take account of filtering by bikes when the cars grind to a halt.

I'd like to meet the Irish car driver who would give a cyclist half a car space to ride in though, half an inch is more typical :rolleyes:

Lennoxschips

yeah, i've taken the equivalent for trucks into account and the amount of containers that can go on the betuwe rail link has also been looked into.

all i need to know now is what types of roads are needed for my traffic

still waiting on the NRA, DTO, Rijkswaterstaat, Gemeente Rotterdam and god knows who else for an answer

feck it, i'll take the irish planning route... sure i'll stick in dual carriagewat and i'll be grand

Zaph0d

I think the NRA uses the Highway Capacity Manual 2000. It's $100, so maybe you can get it from a library.

Victor

Lennoxschips wrote:

feck it, i'll take the irish planning route... sure i'll stick in dual carriagewat and i'll be grand

27,000 PCU/day ~= high quality dual carriageway

160,000 PCU/day ~= 2 x 4 lane motorway or 4 carriageway motorway

Lennoxschips

Thanks for that.

I've also discovered recently that a lane of motorway traffic can handle 1500 PCUs per hour. So I'm sorted.

Zaph0d

Victor wrote:

27,000 PCU/day ~= high quality dual carriageway

160,000 PCU/day ~= 2 x 4 lane motorway or 4 carriageway motorway

Is daily capacity 24 times hourly? I can't imagine any road is that full.

How does capacity vary with load? An extremely congested motorway would carry less vehicles per hour than a free flowing motorway. Presumably, there is some peak load before decline sets in. Anyone know about this stuff?

Lennoxschips

I'm working with peak "rush hour" where 9% of the daily traffic uses the road in that hour.

So if 50,000 PCUs travel your road per day, that means 25,000 in each direction. At the peak hour it's 0.09 x 25,000 = 2250.

Meaning I'll need two lanes to handle rush hour traffic.

(woohoo! now I can proceed to the next phase of the project!)

Victor

Typical traffic flows would be something like this. Obviously weekends will be different and locations and tidal directions will also be different.

Middle of night - very little traffic
From 5 am - deliveries and early commuters
7am-9/10am main rush
10am-2pm slight decrease
2pm-5pm gradual build to rush hour, schools going home
5-7pm longer, less intense rush
7pm-1am straightline decline

The middle of night lull means you loose maybe 15-20% of 24x hourly flow, so capacity < 24x hourly capacity. You can also implement rush hour measures (cops on point duty) that may not be ecomonic to implement for the whole day.

There were real graphs for the M50 junctions on the Irish Rail presentation for the Dublin Rail Plan if anyone can find them. It shows flows on the roundabout, not the motorway.

weehamster

Is this what your looking for Victor
Click Here

bandraoi

shouldn't you be working with AADT flows.
Any decent traffic engineering book should have the sort of thing you're looking for.
You also need to go to tionestop and dig out the appropriate design standards for what you're doing (should be referenced in the book)

Usually peak capacity is not governed by the road but by the junctions and other traffic constraints.

bandraoi

http://www.amazon.co.uk/exec/obidos/ASIN/0340662794/qid=1117800241/br=3-5/br_lfncs_b_5/026-5300214-4165226

something like this book I'd imagine.

antoinolachtnai

NRA publish numbers from their traffic surveys. for the main roads in Ireland if that's any help. They're on the website somewhere.

I was recently looking for some traffic figures for traffic-lit junctions in Fingal, including Swords. I had found them at one stage on the Web, but then I couldn't find them again. Anybody seen anything like this?

Metrobest

Lennoxschips, you might like to try the EU offices in the Netherlands or Belgium as some of the routes around Rotterdam may carry international traffic.

Capt'n Midnight

ninja900 wrote:

That's probably reasonably accurate in flowing traffic, but doesn't take account of filtering by bikes when the cars grind to a halt.

I'd like to meet the Irish car driver who would give a cyclist half a car space to ride in though, half an inch is more typical :rolleyes:

I've some stuff in the far east where they give cyclists a negative number !
something about them advancing in front of the lights at a junction and stopping drivers entering a junction they can't exit.

Victor

weehamster wrote:

Is this what your looking for Victor
Click Here

Yeah, found the copy I had at home.

I converted the graphs to data. You can interpret as you wish Lennoxschips.

[edit] can't upload Excel file. PM me anyone that wants it.

Lennoxschips

No need for the excel file (many thanks though), those graphs will come in handy in PDF form, especially trying to deduce the needed peak capacity (ie rush hour) when compared to the 24 hour capacity.

great stuff!

Victor

Those three examples show peak flow as 7.1%-10.8% of daily flow = your figure of 9%. Note that you have to work this out for each direction separately.

Count empty trucks, returning with empty loads.

Lennoxschips

Excellent, I'm glad my figure of 9% (which was based on one graph I had of the A4 Amsterdam-Hague motorway) seems to be a realistic number.

I didn't need to go into much detail, as my project is mostly to do with the construction side of things, but I wanted to make sure I had made a decent estimate based on the road usage for now and the future, with the right amount of lanes. It will make my project look better.

Thanks for all your help.

jd

I was thnking about something related to this and looked into it..
Anyway, the optimal speed for traffic throughput is actually 32mph, or about 50 km/hr

http://www.rcocweb.org/about/answer.asp?FAQID=5